Hi Henri,
Henri Sivonen wrote:
> On Aug 20, 2009, at 15:06, Jan Richards wrote:
>
>> Henri Sivonen wrote:
>>> Given enough rope, Web authors do the wildest things for the craziest
>>> reasons. However, here's a plausible non-crazy failure scenario:
>>> Author A creates a document using an authoring tool and fails to make
>>> the document accessible. The authoring tool inserts the "ignore"
>>> marker. Later, author B in author A's organization addresses the
>>> problem that the document is inaccessible. Author B adds sensible alt
>>> text using a text editor. While author B has read introductions to
>>> Web accessibility to know about alt, author B isn't aware of the
>>> finer points of HTML syntax and fails to remove the "ignore" marker.
>>> Now the document is still inaccessible in UAs that honor the "ignore"
>>> marker. Author B could even test the document in older UAs without
>>> noticing the problem.
>>
>> I see. Perhaps this could be addressed somewhat by advising authoring
>> tools to automatically undo the "missing" mechanism if an author edits
>> the @alt value.
>
> That author B uses a text editor and not an HTML-aware authoring tool is
> a key part of the scenario. I think it's a realistic key part.
>
> The way to mitigate this is to make only validators and authoring tools
> sensitive to the "missing" marker and not to make browsers/AT sensitive
> to it at all.
I agree re: validators and authoring tools.
For browsers and ATs I'd suggest they look at the @alt value and
"missing" mechanism together. If @alt="" or " " and "missing"=TRUE then
it's probably a good idea for UAs/ATs to trust the "missing" and attempt
a repair (e.g., by looking at the file name, etc.). If @alt has a longer
value and "missing"=TRUE then users might have an option setting to view
the @alt value anyway.
Cheers,
Jan